共查询到17条相似文献,搜索用时 171 毫秒
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本文基于AVL-boost建立一维发动机仿真模型,对采用无凸轮式配气型线的发动机整机性能进行数值模拟。仿真结果表明:采用无凸轮式配气型线可以根据不同工况灵活调整气门升程及相位,能够有效降低发动机部分负荷工况下的换气损失,改善发动机的动力性及燃油经济性,为无凸轮式配气机构的控制应用提供了理论依据。 相似文献
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全球汽车保有量每年都在不断地增加,汽车工业的高速发展给全社会带来资源短缺和环境污染的问题。提高发动机燃烧效率是传统汽车节能减排的重要方面。本项目研究一种新型的电磁驱动配气机构用来取代原有的凸轮轴配气机构,以克服由于凸轮轮廓固定而导致的配气定时和升程无法调节的弊端。它能更灵活的的控制气门的升程,开闭定时从而可以提高燃烧的效率和燃油经济性,降低污染。本文先利用有限元Maxwell 2D模块计算气门所受的电磁力大小,再建立电磁驱动配气机构的有限元静力模型,利用Workbench计算机构的应变和应力值,检验其强度是否满足要求。 相似文献
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为验证自行研制的动圈式电磁驱动配气机构(EMVT)柔性化控制气门运动的能力及其运行稳定性,搭建了以数字信号处理器(DSP)为核心控制器的试验平台并进行了相关性能试验。提出了EMVT实际应用于发动机进气系统的控制系统方案,搭建了基于dSPACE系统和CAN总线的半实物仿真试验平台。试验结果表明,该电磁驱动配气机构的气门开启和关闭的最小过渡时间为2.7ms,平均气门落座速度为0.028m/s ,满足高速响应和缓落座的要求,且功耗较小;每个气门均可独立控制;可对配气定时、气门开启持续期、气门过渡时间、气门升程等参数实现柔性化调节;在低、中、高转速下都能长时间稳定运行。半实物仿真试验也验证了所提控制系统方案的可行性。 相似文献
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可变气门升程技术能在发动机不同转速、不同负荷时匹配合适的气门升程,是解决发动机燃油经济性和排放性二者矛盾的核心技术之一。文章以有关汽车公司推出的典型产品为例,对当前具有代表性的发动机可变气门升程技术的结构、工作原理进行简介,并对它们的性能特点进行比较。 相似文献
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以某1.5 L增程式发动机为研究对象,建立并标定其CAE仿真模型,利用实验设计(DOE)技术对气门升程曲线、进气歧管及进气道结构进行优化研究;对改型后的增程式发动机进行了全面的台架试验标定。实验和分析结果表明:新的气门升程曲线提高了低速段扭矩,尤其是转速为1200r/min和2800r/min时,扭矩分别增大了10%和12%;优化了进气道结构,平均滚流比大幅提升至原来的1.5~2.2倍;优化后的增程式发动机高效率区的实验等油耗值为250g/(kW·h),相对原机的实验等油耗值,增加了近3倍。 相似文献
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针对传统双发动机洗扫车排放差、噪声大、污染严重的问题,采用增程式混合动力洗扫车动力系统,提出了一种稳态分配+动态协调的能量管理策略。通过稳态能量管理对工作模式进行了划分,在此基础上设计了一种基于发动机转速模糊PID+电池下垂控制的动态协调控制方法,该方法以燃油消耗量最优为控制目标,通过控制发动机动力输出和抑制充放电功率波动,从而维持电池充放电平衡,最终实现洗扫车最佳燃油经济性。仿真分析结果表明:和传统双发动机洗扫车相比,采用所设计的控制策略,发动机转速控制平稳,转场模式节油率达到17.7%,洗扫模式节油率达到37.1%,验证了控制策略的合理性。 相似文献
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WONG Pak-kin TAM Lap-mou LI Ke 《机械工程学报(英文版)》2007,20(5):80-86
In modern four-stroke engine technology, variable valve timing and lift control offers potential benefits for making a high-performance engine. A novel electro-hydraulic fully variable valve train for four-stroke automotive engines is introduced. The construction of the nonlinear mathematic model of the valve train system and its dynamic analysis are also presented. Experimental and simulation results show that the novel electro-hydraulic valve train can achieve fully variable valve timing and lift control. Consequently the engine performance on different loads and speeds will be significantly increased. The technology also permits the elimination of the traditional throttle valve in the gasoline engines and increases engine design flexibility. 相似文献
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Jinyoung Cha Junhong Kwon Youngjin Cho Simsoo Park 《Journal of Mechanical Science and Technology》2001,15(10):1442-1450
The EGR system has been widely used to reduce nitrogen oxides (NOx) emission, to improve fuel economy and suppress knock by using the characteristics of charge dilution. However, as the EGR rate at a given engine operating condition increases, the combustion instability increases. The combustion instability increases cyclic variations resulting in the deterioration of engine performance and emissions. Therefore, the optimum EGR rate should be carefully determined in order to obtain the better engine performance and emissions. An experimental study has been performed to investigate the effects of EGR on combustion stability, engine performance, NOx and the other exhaust emissions from 1. 5 liter gasoline engine. Operating conditions are selected from the test result of the high speed and high acceleration region of SFTP mode which generates more NOx and needs higher engine speed compared to FTP-75 (Federal Test Procedure) mode. Engine power, fuel consumption and exhaust emissions are measured with various EGR rate. Combustion stability is analyzed by examining the variation of indicated mean effective pressure (COVimep) and the timings of maximum pressure (Pmax) location using pressure sensor. Engine performance is analyzed by investigating engine power and maximum cylinder pressure and brake specific fuel consumption (BSFC). 相似文献
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A variable valve timing (VVT) can improve fuel efficiency, reduce CO2 emissions and increase torque output enabling optimization
of these outputs at different engine conditions. To achieve VVT in internal combustion engine, new devices such as mechanical,
hydraulic, motor-driven and electromagnetic actuators have been developed in past years to replace the conventional camshaft
valve train system used currently. Among these, the electromagnetic actuator using solenoids is the most advanced system to
provide the most flexibility to valve timing, but it has critical drawback of high power consumption. In this paper, a new
electromagnetic engine valve actuator that uses permanent magnets to latch the valve is introduced. 相似文献